Nonhazardous polymerization initiators

ABSTRACT

A nonhazardous ketone peroxide composition is disclosed comprising a ketone peroxide, trischloroethyl phosphate and a glycol.

United States Patent McCloskey et a].

[151 3,692,841 51 Sept. 19, 1972 [54] NONHAZARDOUS POLYMERIZATION INITIATQRS [72] Inventors: Chester M. McCloskey, Altadena,

' Calif. 91001; Donald E. Rees, Po-

mona, Calif. 91166; George L.

Hoff, Covina, Calif. 91722 [52] US. Cl. ..260/610 R [51] Int. Cl ..C07c 73/00 [58] Field of Search ..260/610 R, 610 B [56] References Cited UNITED STATES PATENTS 7/1967 Mageli et a1. ..260/610 R 2/1964 Blaser et al. ..260/610 R Primary Examiner-Demand Helfin Assistant Examiner-W. B. Lone Attorney-Chester M. McCloskey ABSTRACT A nonhazardous ketone peroxide composition is disclosed comprising a ketone peroxide, trischloroethyl phosphate and a glycol.

12 Claims, No Drawings NONHAZARDOUS POLYMERIZATION INITIATORS This application is a continuation in part of copending application Ser. No. 610,208 filed Dec. 27, 1966 now abandoned.

This invention relates to a new nonhazardous polymerization'initiator composition.

lt is an object of this invention to provide essentially non-aqueous ketone peroxide compositions that are stable, of low flamability and nonhazardous for use as a polymerization initiator.

It is another object of this invention to provide a polymerization initiator composition of exceptional activity.

Methyl ethyl ketone peroxide compositions containing sufficient water (often 20 percent or more) to render them of low flamability and nonhazardous are well known in the art. A coupling agent is usually employed to prevent phase separation. Water is very effective in lowering the flamability since its high heat capacity and heat of vaporization provide an energy sink into which the heat of decomposition of the ketone peroxide can be absorbed.

These compositions are employed principally in the low temperature polymerization or curing of unsaturated polyester vinyl monomer resins commonly known in the art as polyester resins."

While water (in adequate quantity) is effective in conferring low flamability and nonhazardous properties on ketone peroxide composition, its limited solubility in polyester resins and other vinyl monomers often prevents the ready dispersion or dissolution of the methyl ethyl ketone peroxide composition, resulting in nonuniform polymerization. This is particularly a problem in spray applications employing polyester resins wherediffusion of the peroxide composition into the resin droplets is necessary for proper cure, since no physical mixing is involved. The problem is further complicated since ethylene and propylene glycols which have been employed as coupling agents also have a low solubility in the polyester resins.

The hazardous character or organic peroxides in general and ketone peroxides in particular is well known in the art. The lower members of the ketone peroxide family must be diluted with a phlegmetizer or desensitizer before they can be shipped or handled with relative safety. The term nonhazardous" as used herein encompasses not only the phlegmetization or desensitization to shock and fire such as is provided by dimethyl phthalate to methyl ethyl ketone peroxide, but suppression as well of the acceleration during burning that is characteristic of organic peroxides as well as the rapid or explosive decomposition on heating to high temperatures. The object of the preparation of nonhazardous ketone peroxide compositions is to increase the safety with which such compositions can be shipped, employed and stored so that they can be handled without the special precautions otherwise required. This has become especially important with the introduction of methyl ethyl ketone peroxide into general household use.

The terms stable and stabilizer" unfortunately have double meanings. They are used in some instances to refer to the loss of activity with time. Thus, a peroxide compound that loses less activity (active oxygen) over a specified length of time is said to be more stable. On the other hand stable" and stabilizer" are also used to refer to desensitized or phlegrnatized compounds. Thus a compound may rapidly lose activity with time but be insensitive to shock and said to be stable. In still another case a compound can be stable in activity, stable to shock yet decompose explosively on heating to high temperatures and be said to be unstable." Thus the term nonhazardous is used herein as described above rather than the word stable.

It has been discovered in accordance with the present invention that trischloroethyl phosphate although ineffective in conferring nonhazardous properties when used alone with a ketone peroxide is very effective when employed in combination with a glycol and yields a nonhazardous composition of greatly increased solubility in polyester resins as well.

That trischloroethyl phosphate exhibited the same accelerating burning characteristics as dimethyl phthalate when used with a ketone peroxide such as methyl ethyl ketone peroxide as a phlegmetizer was unexpected since phosphates .are sometimes added to reduce the flamability of a composition. That a combination of trischloroethyl phosphate and a glycol would be effective was totally unexpected.

It was found that a wide range of glycols could be employed with trischloroethyl phosphate. Ethylene glycol, propylene glycol and their polymers to tetraethylene glycol mol. wt. 194) were operable. The homologues of ethylene glycol were found to be effective up to and including 2-ethyl-l,3-hexanediol (mol. wt. 146). In both cases the effectiveness of the glycol diminishes as the molecular weight is increased and the ratio for glycol to trischloroethyl phosphate must be increased to be operable.

- The term alkylene glycol" as used herein refers to alkane, cycloalkane and aralkane diols. Thus ethylene glycol, cyclohexane-l ,3-diol, 2-ethyll ,3-hexanediol and l-phenyl-l,2-ethanediol would all be alkylene glycols and all are effective.

Ketone peroxide compositions, particularly of the .lower members usually contain water particularly when glycols are present. Water up to 15 percent can be tolerated, less than 10 percent is desirable and 5 percent or less preferred.

With methyl ethyl ketone peroxide as the model, concentrations of ketone peroxide up to 68 percent 12.5 percent active oxygen) can be safely formulated. However, a 60 percent concentration (11 percent active oxygen) or slightly below is preferred. The ratio by weight of trischloroethyl phosphate to propylene glycol can be varied between 8 to 2 and l to 9 but the preferred ratio is l to l.= With the higher glycols a ratio between 7.5 to 2.5.and 2.5 to 7.5 is desired. The optimum ratio however depends on the glycol employed.

While the present invention applies to ketone peroxides in general, such as peroxides from methyl amyl ketone, ethyl amyl ketone and methyl iso-butyl ketone, it is particularly useful for the peroxides of the lower molecular weight ketones such as methyl ethyl ketone and methyl propyl ketone. Higher molecular weight ketones (over mol. wt. 128) while operative are not of real importance commercially in the instant compositions since their lower active oxygen concentration greatly reduces their hazard. Methyl ethyl ketone nines (351a peroxide and its mixtures with cyclohexanone peroxide which are liquids are especially operable. The term ketone peroxide as used here is employed in the sense of common commercial usage. It refers to the hydroxyhydroperoxy compounds and their functional polymers of commerce. The cyclic trimeric acetone peroxide has no functional hydroxy or hydroperoxy groups and is not commonly employed in free radical initiated polymerization thus the ketones from which operable peroxides are obtained are those encompassed by the aliphatic hydrocarbon monoketones of molecular weight from 72 to 128.

The methyl ethyl ketone peroxide compositions of the instant invention have an exceptionally high activity giving rapid gel with polyester resins and related monomers. These gels are much faster than those of commercial dimethyl phthalate base methyl ethyl ketone peroxides.

The preparation of the ketone peroxide compositions can be carried out by reacting the ketone with hydrogen peroxide in the presence of an acid and a mixture of trischloroethyl phosphate and a glycol, neutralizing and removing the water. The preferred method is to react the ketone and hydrogen peroxide in the presence of an acid and the glycol, neutralize, add the trischloroethyl phosphate and remove the water preferably by distillation. Consistently higher solubilities and lower flamabilities are given by this method. Whether the trischloroethyl phosphate is added before or after the neutralization is unimportant.

The following examples are illustrative only and are not meant to limit the scope of the invention.

EXAMPLE 1 A typical unsaturated polyester resin or polyester resin as they are commonly called used in the following examples was prepared as follows: 65 parts alkyd resin,

acid No. 45-50 prepared from 1 mole maleic an-- EXAMPLE 2 The term PVT test in the examples, refers to a pressure vessel test developed in Holland by Dr. E. W. Lindeljer at the Technological Laboratory of the National Defense Research Organization, and work with it in this country is described by CT. Mageli et al, Ind. Eng. Chem., 56, 18 (1964). It consists essentially of a pressure vessel into which a sample is placed in a metal cup. On the top is fitted a burst diaphragm calibrated for 100 psi. On the side is a fitting into which discs having varying apertures can be inserted. Using a standard heating rate the smallest aperture that can be tolerated without rupture of the burst diaphragm for a given compound is determined. The smaller the aperture the less hazardous the compound.

1 EXAMPLE 3 Methyl ethyl ketone peroxide compositions were obtained by reacting 88.5 g. of methyl ethyl ketone and l 1 l g. of 50 percent hydrogen peroxide in the presence of 0.2 g. of sulfuric acid and 100 g. of phlegmetizer as set forth below at 45C for 3 95 hours. The reaction was neutralized with sodium bicarbonate and concentrated under vacuum to an active oxygen concentration of 10.6. The time to gel was determined at 1 percent concentration with the standard polyester resin described in Example 1. The compositions were tested in the bomb described in Example 2 known as the PVT test.

EXAMPLE 4 The solubilities of several methyl ethyl ketone peroxide compositions (active oxygen 10.6 percent) prepared by the method of Example 3 were determined in a polyester resin similar to Example 1 but without the cobalt naphthenate and compared to a commercial nonhazardous methyl ethyl ketone peroxide composition*.

ml. required to give haziness to 10 g of resin at Phlegmetizer ratio trischloroethyl phosto propylene glycol 21C 10/0 5.0 9/1 3.4 5/5 1.5 2.5/7.5 0.7 0/10 0.65 Norox W-60 0.45

'Norox W-60 a product ofNorac Co., Inc. ofAzusa, California.

EXAMPLE 5 The relative burning characteristics of methyl ethyl ketone peroxide compositions prepared by the method of Example 3 were determined by placing 4 g of the composition in a 30 mm diameter and 30 mm high aluminum foil cup inserting a wick and igniting. The burning time and maximum flame height were determined.

In many instances the maximum flame height was reached for only a short period near the end of burning. Active oxygen concentration is 10.6 percent unless noted.

Effect of Phlegmetizer Composition 3-0 Polypropylene glycol dibenzoate a. an,

Ratio: trischloroethyl phosphate to the following:

l,4-butanediol 5/5 l4 4-30 l,3-butanediol 5/5 16 4-4l 2-methyl-2,4-pentanediol 5/5 23 2-45 Effect of Active Oxygen Concentration Ratio: trischloroethyl phosphate Water content prior to addition, 6.5%.

EXAMPLE 6 Several methyl ethyl ketone peroxide compositions were prepared by the method of Example 3 utilizing as the phlegmetizer equal portions of trischloroethyl phosphate and one of the glycols listed below, Prepared as well were two compositions containing a mixture of cyclohexanone peroxide and methyl ethyl ketone peroxide with trischloroethyl phosphate and a glycol. Flash point and fire point were determined together with gel time and time to initial cure at 1 percent concentration in the resin of Example 1. The compositions were tested with a 2 mm aperture in the PVT apparatus 50 described in Example 2.

Gel Cure (passes 4mm) The following compositions contained cyclohexanone peroxide as well as methyl ethyl ketone:

Propylene glycol 220 220 8,0 95 passes Tetraethylene glycol 224 224 l4.0 82 fails (passes 4 mm) Methyl ethyl ketone peroxide in dimethyl phthalate 45 87 fails (passes 10) A commercial methyl ethyl ketone peroxide composition.

EXAMPLE 7 Several methyl ethyl peroxide compositions were prepared by the method of Example 3 utilizing 1 part of trischloroethyl phosphate to 3 parts of glycol.

5 Glycol. Employed PVT Test aperture 2 mm 2-Ethyl-l,3-hexanediol fails-(passes 4 mm) l-lexylene glycol passes Tetraethylene glycol passes Tripropylene glycol fails-(passes 4 mm) EXAMPLE 8 A methyl amyl peroxide composition was prepared by the method of Example 3 utilizing equal parts of 5 trischloroethyl phosphate and 2-ethyll ,3 hexanediol.

PVT test passes EXAMPLE 9 A methyl ethyl ketone peroxide composition containing equal parts of trischloroethyl phosphate and propylene glycol and an active oxygen concentration of 10.6 percent was prepared by the method of Example 3 5 except that the trischloroethyl phosphate was not added until the reaction was completed and the solution neutralized, but before removing the water under vacuum. Its properties were as follows:

Accelerated aging ll0F 30 days 2.5% loss in (0) PVT test 2 mm passes Burning test 30 mm cup flame height 10 in. burning time 3 min. 25 sec.

Solubility in 10g of resin 1.8 min.

Gel time 1% cone.

Resin of Example I 25C 10.2 min.

PVT test Gel time as above passes 2 mm [3.5 min.

We claim: l. A nonhazardous methyl ethyl ketoneperoxide composition containing less than 15 percent water, comprising methyl ethyl ketone peroxide, trischloroethyl phosphate, and a glycol selected from the group consisting of dipropylene glycol, a 0 polyethylene glycol of molecular weight not exceeding 194 and an alkylene glycol of molecular weight not exceeding 146.

2. The composition of claim 1 in which the glycol is propylene glycol.

3. The composition of claim 1 in which the 'glycol is hexylene glycol.

4. A nonhazardous ketone peroxide composition containing less than 15% water comprising a ketone peroxide prepared from an aliphatic hydro-carbon monoketone of molecular weight from 72 to 128 inclusive, trischloroethyl phosphate and a glycol selected from the group consisting of polypropylene, and polyethylene glycols of molecular weight not exceeding 194 and an alkylene glycol of molecular weight not exceeding 146 and the ratio by weight of trischloroethyl phosphate to glycol is between 8 to 2 and l to 9, the active oxygen being 12.5 percent or less.

5. A nonhazardous ketone peroxide composition containing less than percent water comprising a ketone peroxide selected from the group consisting of methyl ethyl ketone peroxide and a mixture of methyl ethyl ketone peroxide and cyclohexanone peroxide, trischloroethyl phosphate and a glycol selected from the group consisting of polypropylene, and polyethylene glycols of molecular weight not exceeding I94 and an alkylene glycol of molecular weight not exceeding 146 and the ratio by weight of trischloroethyl phosphate to glycol is between 8 to 2 and l to 9, the active oxygen being 12.5 percent or less.

6. The composition of claim 5 in which the glycol is an alkylene glycol of molecular weight not exceeding 146.

7. The composition of claim 6 in which the alkylene glycol is propylene glycol.

8. The composition of claim 7 in which the ratio by weight of trischloroethyl phosphate to propylene glycol is between 7.5 to 2.5 and 2.5 to 7.5.

9. The composition of claim 7 in which the ketone peroxide is methyl ethyl ketone peroxide.

10. The composition of claim 8 in which the ketone peroxide is methyl ethyl ketone peroxide.

11. The composition of claim 6 wherein the glycol is hexylene glycol.

12. The composition of claim 11 wherein the ratio by weightof trischloroethyl phosphate to hexylene glycol is between 7.5 to 2.5 and 2.5 to 7.5.

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2. The composition of claim 1 in which the glycol is propylene glycol.
 3. The composition of claim 1 in which the glycol is hexylene glycol.
 4. A nonhazardous ketone peroxide composition containing less than 15% water comprising a ketone peroxide prepared from an aliphatic hydro-carbon monoketone of molecular weight from 72 to 128 inclusive, trischloroethyl phosphate and a glycol selected from the group consisting of polypropylene, and polyethylene glycols of molecular weight not exceeding 194 and an alkylene glycol of molecular weight not exceeding 146 and the ratio by weight of trischloroethyl phosphate to glycol is between 8 to 2 and 1 to 9, the active oxygen being 12.5 percent or less.
 5. A nonhazardous ketone pEroxide composition containing less than 15 percent water comprising a ketone peroxide selected from the group consisting of methyl ethyl ketone peroxide and a mixture of methyl ethyl ketone peroxide and cyclohexanone peroxide, trischloroethyl phosphate and a glycol selected from the group consisting of polypropylene, and polyethylene glycols of molecular weight not exceeding 194 and an alkylene glycol of molecular weight not exceeding 146 and the ratio by weight of trischloroethyl phosphate to glycol is between 8 to 2 and 1 to 9, the active oxygen being 12.5 percent or less.
 6. The composition of claim 5 in which the glycol is an alkylene glycol of molecular weight not exceeding
 146. 7. The composition of claim 6 in which the alkylene glycol is propylene glycol.
 8. The composition of claim 7 in which the ratio by weight of trischloroethyl phosphate to propylene glycol is between 7.5 to 2.5 and 2.5 to 7.5.
 9. The composition of claim 7 in which the ketone peroxide is methyl ethyl ketone peroxide.
 10. The composition of claim 8 in which the ketone peroxide is methyl ethyl ketone peroxide.
 11. The composition of claim 6 wherein the glycol is hexylene glycol.
 12. The composition of claim 11 wherein the ratio by weight of trischloroethyl phosphate to hexylene glycol is between 7.5 to 2.5 and 2.5 to 7.5. 